1. Field of the Invention
The present invention relates to a printer that creates labels by printing print data onto a tape and then cutting the tape, and to a printing program executed by such a printer.
2. Description of the Related Art
In one type of conventional printer, heating elements arranged on a thermal head generate heat in order to print printing data that includes any characters, patterns, or the like onto a roll of elongated tape, and this tape is then cut to make it possible to easily create labels. This type of printer utilizes a printing scheme in which the elongated tape is passed together with an ink ribbon between the thermal head and a platen roller, and the portion of the ink ribbon that is heated by the thermal head is thermally transferred to the surface of the elongated tape as a printed image that includes characters, patterns, or the like. In this type of printer, the thermal head generates heat in accordance with the line data representing each single line in the printing data while ink ribbon and the tape are fed through one line at a time, thereby sequentially printing and outputting the printing data one line at a time.
This type of thermal transfer printer prints by heating the heating elements in the thermal head, and therefore when a given heating element is heated, that heat also gets transmitted to the adjacent heating elements. In other words, the temperature of the adjacent heating elements becomes higher than the target temperature, which can cause additional ink to melt and thereby result in the printed characters and the like becoming smudged or blurry. In other words, the effects of the heat generated by nearby heating elements can result in a decrease in printing quality.
In one technology for solving this problem, the temperature near the thermal head is measured using a thermistor arranged near the thermal head and then fed back to the printer in order to change the energizing time for the thermal head while printing.
In another technology, a control process that uses the ratio of printing data relative to the effective printing dot count of the thermal head (a black dot ratio) to divide up the printing data and change the printing speed is implemented.
Japanese Patent Application Laid-Open Publication No. H6-143648, for example, discloses a thermal transfer recorder that detects the number of heating elements to which pulses can be applied and then controls the number of pulses applied to those heating elements according to the detection results.
However, due to the time lag between changes in the temperature near the thermal head and changes in the temperature of the thermal head itself, it is not possible to print using a suitable energizing time, nor is it possible to maintain satisfactory printing quality.
Moreover, even when the printing speed is changed according to the black dot ratio, variations in printing quality still tend to occur due to differences in the distribution of black dot data.
The present invention was made in light of the foregoing and aims to provide a printer that makes it possible to print with high quality, as well as a printing program to be executed by that printer.
Accordingly, the present invention is directed to a scheme that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.